Abstract
Background Recently, we constructed a noninvasive screening algorithm aiming at earlier chronic
thromboembolic pulmonary hypertension (CTEPH) detection after acute pulmonary embolism
(PE), consisting of a prediction score and combined electrocardiography (ECG)/N-terminal
pro-brain natriuretic peptide (NT-proBNP) assessment. The aim of this study was to
confirm the algorithm's sensitivity for CTEPH detection and to evaluate the reproducibility
of its individual items.
Methods Two independent researchers calculated the prediction score in 54 consecutive patients
with a history of acute PE and proven CTEPH based on clinical characteristics at PE
diagnosis, and evaluated the ECG and NT-proBNP level assessed at the moment of CTEPH
diagnosis. Interobserver agreement for the assessment of the prediction score, right-to-left
ventricle (RV/LV) ratio measurement on computed tomography pulmonary angiography,
as well as ECG reading was evaluated by calculating Cohen's kappa statistics.
Results Median time between PE diagnosis and presentation with CTEPH was 9 months (interquartile
range: 5–15). The sensitivity of the algorithm was found to be 91% (95% confidence
interval [CI]: 79–97%), indicating that 27 of 30 cases of CTEPH would have been detected
when applying the screening algorithm to 1,000 random PE survivors with a 3% CTEPH
incidence (projected negative predictive value: 99.7%; 95% CI: 99.1–99.9%). The interobserver
agreement for calculating the prediction score, RV/LV ratio measurement, and ECG reading
was excellent with a kappa of 0.96, 0.95, and 0.89, respectively.
Conclusion The algorithm had a high sensitivity of 91% and was highly reproducible. Prospective
validation of the algorithm in consecutive PE patients is required before it can be
used in clinical practice.
Keywords
pulmonary embolism - CTEPH - screening algorithm - sensitivity - reproducibility
